The invention pertains to devices for storing gases and fluids under pressure. More particularly, the invention relates to pressure vessels that are formed out of flexible materials and that can be made to conform to a variety of shapes.
Typically, pressure vessels capable of containing liquids or gases at significant pressures have involved fixed shape cylinders or spheres formed of high-strength metals such as steel or aluminum. Such pressure vessels, while successful for their designed applications, involve a number of problems. First, such metallic cylinders are relatively heavy compared to the gases or fluids that they contain. Second, pressure cylinders contain all of the gas or liquid in a single space. Should the vessel rupture, the entire vessel is destroyed, often with a violent explosion sending shards of metal in all directions. Third, metallic cylinders have a definite shape and cannot be adapted to fit readily in many space-constrained applications. The present invention involves a number of small cells of an elongated tubular shape linked to each other by collecting end caps. The result of this design is that the pressure vessel may be readily formed into a variety of useful shapes to accommodate special applications. A pressure vessel of this type can be lightweight, adaptable to a variety of spaces and unusual applications, and is inherently safer in rupture situations.
Various designs have been developed using elongated tubular shaped vessels, most in the area of radiators and heat exchangers. U.S. Pat. No. 6,390,187 issued to Marechal et al. discloses a heat exchanger with flexible tubes. The tubes may be made from a plastic material and are designed to carry a heat-exchanging fluid capable of cooperating with an air stream circulating through the exchanger. The invention is intended to describe the method by which the tubes are maintained in parallel rows. The tubes are made from a plastic material and communicate by way of their extremities with two manifolds. The manifolds include collector plates equipped with apertures that thus form a means for holding the tubes in place. The tubes are arranged in rows that are parallel to one another by a distance corresponding to the tube thickness so that the various rows are adjacent in pairs of respective tubes of two consecutive pairs. The tubes generally exhibit a sinusoidal shape and thus aligned for expanding and contraction so that the tubes may utilize the flexible characteristics and maintain the integrity of the system.
U.S. Pat. No. 4,450,902 issued to Bosne, is directed to a heat exchanger in particular for an atmospheric cooling tower. The exchanger utilizes synthetic plastic material for the tubes that has one fixed header while the remainder of the exchanger is mounted by suspension to allow for free expansion. A chamber has a heat exchanger with a series of tubes extending throughout the length of chamber. The exchanger comprises a battery of smooth tubes made of a synthetic material. The tubes of the heat exchanger are fixed to the support structure at one of the ends and is freely suspended by a suspension members to allow for expansion and contraction.
U.S. Pat. No. 5,158,134, issued to Mongia et al., discloses a fully floating tube bundle. The exchanger comprises a plurality of fluid carrying tubes that is free floating with no direct contact between the end plates or center plate. Thus, the tubes are free to move with respect to the end plates and center plate as to eliminate damage by vibration and temperature changes.
U.S. Pat. No. 4,114,683 issued to Verlinden describes a flexible tube type fluidxe2x80x94fluid heat exchanger. The exchanger comprises a plurality of flexible synthetic tubes extending in a curved path between a pair of headers. The tubes are connected to headers and are constructed of a flexible plastic material so they may easily conform to the curvature of the wall 11.
U.S. Pat. No. 5,651,474 issued to Callaghan et al is directed to cryogenic structures that are vessels made of a durable plastic material and are adapted to contain cryogenic materials such as fuel. The structures are made of a fiber network impregnated with a matrix of thermal set plastics and have three tank lobes of a composite plastic reinforced with fibers. The tank lobes may be filament-wound on a rotating mandrel while the fibers are pre-impregnated with resin. Another technique is to heat the tank skins allowing the pre-impregnated fiber layers to fuse together and then cool so as to set up a solid matrix that grips the fibers.
While other variations exist, the above-described designs involving elongated tubular shaped vessels are typical of those encountered in the prior art. It is an objective of the present invention to provide a flexible pressure vessel that is capable of maintaining gasses or liquids at relatively high pressures. It is a further objective to provide this capability in a vessel that is light in weight and that presents a significantly reduced risk of injury in rupture situations. It is a still further objective of the invention to provide a pressure vessel that may be easily adapted to a variety of space constraints. It is yet a further objective to provide a pressure vessel that is durable, easily serviced, and that may be produced inexpensively.
While some of the objectives of the present invention are disclosed in the prior art, none of the inventions found include all of the requirements identified.
A cellular reservoir flexible pressure vessel providing the desired features may be constructed from the following components. A plurality of flexible tubes is provided. Each of the flexible tubes are formed of resilient material and have an outer surface, an inner surface, a first end and a second end.
First and second end caps are provided. Each of the end caps have a receptacle for either of the first or second ends of each of the flexible tubes, a collecting reservoir, a surrounding outer rim and an outer perimeter perpendicular to the surrounding outer rim. At least one of the first and second end caps have a passageway connecting to the collecting reservoir for connection to either a passageway of another pressure vessel or a valve. Each of the receptacles has a surrounding wall, a base and an orifice penetrating the base and connects the receptacle to either the collecting reservoir or the passageway. The wall has an interior surface. The interior surface is sized and shaped to fit frictionally over the outer surface of one of the flexible tubes at either the first or second ends. The collecting reservoir has an outer surface and connects the base of each of the receptacles to a common space. The common space is either closed or connected to the passageway. The surrounding outer rim extends outwardly from the outer surface of the collecting reservoir for a first predetermined distance along the flexible tubes and serves to constrain the flexible tubes.
Means are provided for securing the first and second end caps to the flexible tubes. A valving means is provided. The valving means is capable of controlling a flow of either a liquid or a gas through the passageway and is attached to a distal end of the passageway. When the flexible tubes are inserted into the receptacles of the end caps and secured thereto, a flexible pressure vessel will be formed capable of containing either a liquid or a gas at high pressure.
In a variant of the invention, the means for securing the first and second end caps to the flexible tubes is selected from the group comprising: radio frequency welding, high-strength adhesive, mechanical fastening and sonic welding.
In another variant of the invention, a protruding rim is provided. The protruding rim is located at the outer perimeter of the first and second end caps and upper and lower receiving notches located above and below the protruding rim. A reinforcing ring is provided. The reinforcing ring has an inner surface, an outer surface and is formed of high-strength material and is sized and shaped to fit tightly about the outer perimeter of the end cap. The reinforcing ring has an upper and lower projecting ribs and a central receiving notch located between the upper and lower projecting ribs. The projecting ribs are sized, shaped and located to fit the upper and lower receiving notches of the end cap. The central receiving notch is sized, shaped and located to fit the protruding rim of the end cap. The reinforcing ring has an aperture. The aperture extends from the inner surface to the outer surface and is sized, shaped and located to accommodate the passageway of the end cap. When the reinforcing ring is located about the outer perimeter of the first and second end caps, the pressure handling capacity of the pressure vessel is increased.
In yet a further variant of the invention, a protruding rim is provided. The protruding rim is located at the outer perimeter of the first and second end caps and upper and lower receiving notches located above and below the protruding rim.
Upper and lower reinforcing rings are provided. Each of the reinforcing rings have an inner surface, an outer surface and are formed of high-strength material and are sized and shaped to fit tightly in either of the upper and lower receiving notches. At least one of the reinforcing rings has an aperture. The aperture extends from the inner surface to the outer surface and is sized, shaped and located to accommodate the passageway connecting to the collecting reservoir. When the reinforcing rings are located about the outer perimeter of the first and second end caps, the pressure handling capacity of the pressure vessel is increased. Means are provided for fastening the upper reinforcing ring to the lower reinforcing ring.
In still a further variant of the invention, a protruding rim is provided. The protruding rim is located at the outer perimeter of the first and second end caps. At least one groove located about the outer perimeter above the protruding rim is provided. At least one groove located about the outer perimeter below the protruding rim is provided. Upper and lower reinforcing rings are provided. Each of the reinforcing rings have an inner surface, an outer surface and are formed of high-strength material and are sized and shaped to fit tightly about the outer perimeter on either side of the protruding rim. The reinforcing rings have at least one rib located upon the inner surface thereof, the rib is sized, shaped and located to engage the groove. When the reinforcing rings are located about the outer perimeter of the first and second end caps, the pressure handling capacity of the pressure vessel is increased. Means are provided for fastening the upper reinforcing ring to the lower reinforcing ring.
In yet a further variant of the invention a sintactic foam filler is provided. The foam filler is located within the collecting reservoir of at least one of the first and second end caps. The foam filler has a series of canals through it. Each of the canals connects the orifice of the receptacle to the passageway. An opening in the end cap is provided. The opening provides means for introduction of the sintactic foam into the end cap. A sealing plug is provided. The sealing plug is sized and shaped to fit sealably into the opening in the end cap. When the syntactic foam is introduced into the end cap, the pressure handling capacity of the pressure vessel is increased.
In still a further variant of the invention, a sintactic foam filler is provided. The foam filler is located within the collecting reservoir of at least one of the first and second end caps. The foam is penetrated by a series of flexible microtubes. Each of the microtubes connects the orifice of the receptacle to the passageway. An opening in the end cap is provided. The opening provides means for introduction of the syntactic foam into the end cap. A sealing plug is provided. The sealing plug is sized and shaped to fit sealably into the opening in the end cap. When the microtubes are connected to the orifice of the receptacles in the end cap, the purity of either liquids or gasses stored in the pressure vessel is increased.
In yet a further variant of the invention, an overwrapping of high-strength braiding material is provided. The braiding material extends over the flexible tubes and the first and second end caps. When the flexible pressure vessel is so overwrapped, its pressure-handling capability will be increased.
In another variant, a plastic overcoating is provided. The overcoating further increases the pressure-handling capability of the pressure vessel.
In still a further variant of the invention, a hoop winding with high-strength materials is provided. The hoop winding extends over the flexible tubes and the first and second end caps. When the flexible pressure vessel is so hoop wound, its pressure-handling capability will be increased.
In another variant, a plastic overcoating is provided. The overcoating further increases the pressure-handling capability of the pressure vessel.
In yet a further variant of the invention, a first flexible blanket is provided. The first blanket has an upper surface, a lower surface and is sized and shaped to cover the pressure vessel and extends outwardly beyond the outer edges thereof. The first blanket is fixedly attached at its lower surface to an upper surface of the pressure vessel. A second flexible blanket is provided. The second blanket has an upper surface, a lower surface and is sized and shaped to cover the pressure vessel and extends outwardly beyond the outer edges. The second blanket is fixedly attached at its upper surface to a lower surface of the pressure vessel. When the first and second flexible blankets are attached to the pressure vessel, the pressure handling capability of the pressure vessel will be increased.
In another variant, heavy duty stitching is used to attach the first blanket to the second blanket. The stitching penetrates the first and second blankets and serves to further reinforce and increase the pressure-handling capabilities of the pressure vessel. In still another variant, the heavy duty stitching is high pressure hoop and lock braiding.
In still a further variant of the invention, the cross-sectional shape of the outer surface of the flexible tubing is selected from the group comprising: square, triangular, round, hexagonal, ovoid, octagonal and star shaped.
In yet a further variant of the invention, the cross-sectional shape of the inner surface of the flexible tubing is selected from the group comprising: square, triangle, round, hexagonal, ovoid, octagonal, and star-shaped.
In still a further variant of the invention, the cross-sectional shape of the flexible pressure vessel is selected from the group comprising: square, triangular, round, hexagonal, ovoid, octagonal, pillow shaped, saddle shaped, and a flattened mat shape.
In yet a further variant of the invention, each of the receptacles are of a concave form selected from the group comprising: conical, dome-shaped, ellipsoid and stair-stepped. In a variant, the first and second ends of each of the flexible tubes are sized and shaped to fit sealably into the receptacles.
In still a further variant of the invention, upper and lower reinforcing panels are provided. The reinforcing panels are formed of high-strength woven material and are shaped as a form to cover at least half of a surface area of the pressure vessel with extensions projecting from a perimeter of the form. The reinforcing panels are joined to the outer surface of the pressure vessel, thereby increasing the pressure handling capability of the pressure vessel.
In a variant, the method of adhesion is selected from the group comprising: high-strength adhesive, sonic welding and RF welding.
In another variant, the woven material is prepregnated with either adhesive or laminating material and subjected to heat and pressure.
An apparatus for fabricating a cellular reservoir flexible pressure vessel may be constructed from the following components. A raw plastic storage and feeding unit is provided. The storage and feeding unit contains a supply of raw plastic. A multi-head extruder is provided. The extruder includes a heating facility and is in communication with the feeding unit. A cooling tank is provided. The cooling tank is located downstream from the extruder. A power puller is provided. The puller serves to pull a tubing bundle from the cooling tank. Core tubing forming dies are provided. The forming dies form the tubing bundle into a predetermined shape. A binder head is provided. The binder head has an attached binder tank containing liquid binder material. A binder applicator is provided. The binder applicator comprises a secondary forming die and serves to affix the binder material to the tubing bundle. A cutting unit is provided. The cutting unit comprises a laser calibration facility and serves to cut the tubing bundle to a predetermined length. A conveyer facility is provided. The conveyer facility comprises means for positioning a cut tubing bundle. A rotating head and ram is provided. The head comprises a glue head applicator. The glue head applicator attaches to a glue tank. A plurality of preformed end caps are provided. An automated end cap loader is provided. The end cap loader positions the plurality of end caps. An automated end cap installer attached to the automated end cap loader is provided. The installer serves to attach the end caps to the tubing bundle. A high-intensity UV lamp assembly is provided. The lamp assembly serves to cure the glue.
In a variant of the apparatus for fabricating a cellular reservoir flexible pressure vessel, a plurality of reinforcing rings is provided. The reinforcing rings are formed of high-strength material. A reinforcing ring auto loader is provided. A swivel ram is provided. The ram comprises of a ring loading and placement head. The swivel ram is in cooperation with the ring auto loader and serves to press the reinforcing ring onto the pressure vessel.
In another variant of the apparatus for fabricating a cellular reservoir flexible pressure vessel, either a gas or liquid supply tank is provided. An auto loader test head is provided. The test head is adaptable to fittings on the end caps. A cryogenic test unit in communication with the test head is provided. The test head and the test unit provides means for pressurizing the pressure vessel.
In yet a further variant of the apparatus for fabricating a cellular reservoir flexible pressure vessel, a reinforcing blanket material is provided. A glue spraying mechanism is provided. The mechanism comprises of glue tanks, glue spray heads and glue for attaching the blanket material to the pressure vessel. A blanket material feed mechanism is provided. A press forming tool is provided. The tool is adapted to form the blanket material over the cut tubing bundle and the attached end caps. In a variant, a high-strength thread is provided. A stitching head is provided. The stitching head is adapted to sew the high-strength thread through the reinforcing blanket material.
In still a further variant of the apparatus for fabricating a cellular reservoir flexible pressure vessel includes a high-strength braiding material. A braider is provided. The braider is adapted to position and provide overwrapping of the pressure vessel with the braiding material. A binder spraying mechanism is provided. The spraying mechanism comprises of a binder tank, a binder spray head and binder material.
In yet a further variant of the apparatus for fabricating a cellular reservoir flexible pressure vessel, a high-strength reinforcing ribbon is provided. An automated reinforcing ribbon winding machine is provided. The winding machine comprises of a reinforcing ribbon spool and an auto layout ribbon head. A binder spraying mechanism is provided. The spraying machine comprises of a binder tank, a binder spray head and binder material.
In still a further variant of the apparatus for fabricating a cellular reservoir flexible pressure vessel, means are provided for pulling a series of high tensile strength core wires through orifices in receptacles in the end cap to a passageway in the end cap. Means are provided for injecting sintactic foam through an opening in the end cap. Means are provided for attaching a sealing plug to the opening. Means are provided for removing the core wires from the end cap. When the core wires are removed from the end cap, a series of canals will be formed in the sintactic foam connecting orifices in receptacles in the end cap to the passageway.
In yet a further variant of the apparatus for fabricating a cellular reservoir flexible pressure vessel, means are provided for attaching a series of flexible microtubes to orifices in receptacles in the end cap to a passageway in the end cap. Means are provided for injecting sintactic foam through an opening in the end cap. Means are provided for attaching a sealing plug to the opening. Means are provided for removing the core wires from the end cap. When the microtubes are connected to the passageway, the pressure vessel will provide an ultra clean environment for either liquids or gasses.
In still a further variant of the apparatus for fabricating a cellular reservoir flexible pressure vessel, means are provided for forming a concave receptacle having a shape selected from the group comprising: conical, dome-shaped, ellipsoid and stair-stepped. In a variant, means are provided for forming the first and second ends of each of the flexible tubes to fit sealably into the receptacles.
In yet a further variant of the apparatus for fabricating a cellular reservoir flexible pressure vessel, means are provided for forming upper and lower reinforcing panels. The reinforcing panels are formed of high-strength woven material and are shaped as a form to cover at least half of a surface area of the pressure vessel with extensions projecting from a perimeter from the form. Means are provided for adhering the reinforcing panel to the outer pressure vessel, thereby increasing the pressure handling capability of the pressure vessel.
In a variant of the apparatus for fabricating a cellular reservoir flexible pressure vessel, the method of adhesion is selected from the group comprising: high-strength adhesive, sonic welding and RF welding.
In a final variant of the apparatus for fabricating a cellular reservoir flexible pressure vessel, the woven material is prepregnated with either adhesive or laminating material and subjected to heat and pressure.